If you have a penalty, you can still read and speak your racial
languages unless your Intelligence is lower than 3.

So if you do that, the companion PC is no longer an animal. It's a magical beast, and thus not eligible to be an animal companion.

You could house rule away that restriction of course, but I don't think it's a good idea. If the PC in question wants to play as a magical animal that happens to be the Druid's friend, that would be an easier way to go about it. That lets him play a fully realized character with his own will & ability to interact with the party, instead of what is functionally a trained animal. You could use the monster advancement rules to let him gain levels, or let him take class levels if he wanted to become a Cleric Unicorn or something.

As a note: Animal companions when they hit level 4 do get an ability score increase; this could be added to intelligence...
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RobNov 26 '13 at 14:28

8

" If the PC in question wants to play as a magical animal that happens to be the Druid's friend, that would be an easier way to go about it. " - I think that's a very workable answer - the players can happily interpret/play it like the Druid has 2 companions without needing the mechanics.
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Neil SlaterNov 26 '13 at 15:21

4

@Tridus Interesting! I wonder on the implications; such as wandering around and casting Fox's Cunning on random creatures...
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RobNov 26 '13 at 15:22

1

@Rob Me too! As a DM I'd likely block those spells from working, because animals can't go over 2 and it takes a spell like Awaken to make it not an animal.
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TridusNov 26 '13 at 19:45

3

As an addition, d20pfsrd has a pretty good section on intelligent animals towards the bottom of the page. It explicitly notes that increasing intelligence to 3 allows it to learn a language, but it still has all the restrictions of being a normal animal (and notes differences between an int 3 animal and an awakended animal) and makes no mention of a creature type change.
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EllesedilNov 30 '13 at 2:24

The druid is losing out on his class feature, and the player playing as the companion will be at a disadvantage for the entire game. This is not an ideal situation. Luckily there is a fairly easy solution.

In Pathfinder, Animal Companions are optional. If you want to allow this, force the player who wants to be a druid to take the domain instead of the animal companion class feature. Then make the player who wants to be the animal companion into a magical beast version of whatever animal he/she wants to be.

If the player wants to be a wolf, use the Worg as a guide and create a MB wolf. In the story, this could have been a previous Animal Companion of the druid, but it was awakened, and now they travel together more like equals. The Magical Beast player can then take levels in the MB class or take class levels as it grows.

I don't think your three listed concerns are a real issue because they can be solved by magic and magic items your druid player can easily provide:

Communication

Aside from the obvious temporary solutions (casting Speak with Animals on listeners or Tongues on the wolf itself), your druid may purchase a Circlet of Speaking or a Ring of Eloquence to solve the problem in a more permanent manner. I suggest the Ring, as it specifically mentions its usefulness to druidic wolves and gives 4 languages cheaper than the circlet gives one. Of course, the druid may end up awakening the wolf at some point, such as through prolonged use of a Collar of the True Champion which would remove this issue as well, but make it no longer an animal companion.

Doesn't Have any Magical Powers

It can talk to wolves, and presumably other canines. That's pretty cool. Plus it can take a Use Magic Device skill if its feeling left out in terms of magic, and it can certainly fill some magic item slots. But really, its chilling with a pet druid. That's pretty good access to magic even compared to half-casters like a ranger. Yes, mundane classes are weaker than magic using classes, but they 1) don't have to be completely without access to magic and 2) exist. Your wolf won't be too much worse off than the party rogue, for example. Besides, a small power differential isn't going to ruin your campaign if no one gets jealous. The player looking to play the companion probably isn't looking for optimized power anyways.

Has Few Ways to Interact With Others

This is really solved by the wolf rapidly being able to talk, and is basically just a restatement of your first issue.

Note: I'm coming from a D&D 3e background, so I might be off regarding Pathfinder. The SRD seems to describe what I expected.

Consider XP. The Druid's class levels take the animal companion to be part of his power. By separating the animal companion as another PC, you're removing power from both players. If the Druid PC played both roles, he'd be on par with the rest of the party. Separate, the druid will be maybe two-thirds as powerful as any other PC, and the animal companion maybe one-third as powerful.

You can compensate for this be treating the Druid and Animal Companion as a single member for CR and XP calculations. Just make sure the players realise they will each individually be behind the rest of the party.

Yes, from the mechanics point of view they are treated as single entity. They know, that their individual power will be behind other players and don`t mind.
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LeorisarNov 27 '13 at 11:29

1

It should be pointed out that Druid is a Tier 1 class, and then some. You can take away 1/3 of its power and it's still even against most characters. The animal companion might have a power problem; the druid won't.
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TynamNov 29 '13 at 8:58